@spec count_subscriptions(key()) :: non_neg_integer()

Count the number of active subscriptions for key.

@spec count_subscriptions(key(), Wafer.GPIO.pin_condition()) :: non_neg_integer()

Count the number of active subscriptions for key and pin_condition.

@spec publish(key(), :rising | :falling) :: {:ok, non_neg_integer()}

Publish an interrupt to subscribers that are interested in key and pin_condition.

Searches the registry for all subscribers to are subscribed to pin_condition or :both and publishes the interrupt message to them. The interrupt message takes the form {:interrupt, Conn.t(), :rising | :falling, metadata :: any}.

@spec subscribe(key(), Wafer.GPIO.pin_condition(), Wafer.Conn.t()) :: :ok

Subscribe the calling process to interrupts for the specified pin_condition using the provided key.

See subscribe/4 for more information.

Example

iex> subscribe({MCP230017.Pin, 13}, :rising, conn)
:okcopy

@spec subscribe(key(), Wafer.GPIO.pin_condition(), Wafer.Conn.t(), any()) :: :ok

Subscribe the calling process to interrupts for the specified pin_condition using the provided key.

Arguments

• key a key which uniquely describes the pin. Probably a combination of device name and pin.
• pin_condition either :rising, :falling or :both.
• conn the receiver's connection to the pin, sent back to them in the interrupt message.
• metadata arbitrary data which will be sent to the receiver process in the interrupt message. Defaults to nil.

@spec subscribers?(key()) :: boolean()

Are there any subscribers to key?

@spec subscribers?(key(), Wafer.GPIO.pin_condition()) :: boolean()

Are there any subscribers to key and pin_condition?

@spec subscriptions(key()) :: [
  {Wafer.GPIO.pin_condition(), Wafer.Conn.t(), metadata :: any(),
   receiver :: pid()}
]

Returns a list of all subscriptions to key.

@spec subscriptions(key(), Wafer.GPIO.pin_condition()) :: [
  {Wafer.GPIO.pin_condition(), Wafer.Conn.t(), metadata :: any(),
   receiver :: pid()}
]

Returns a list of all subscriptions key and pin_condition.

@spec unsubscribe(key(), Wafer.GPIO.pin_condition(), Wafer.Conn.t()) :: :ok

Remove all subscriptions for key, pin_condition and conn.